[H]e put the beach sand under a microscope and discovered tiny metal shards mixed in with the ordinary bits of quartz and other materials that he expected to see. Those shards turned out to be shrapnel from the famous World War II invasion. On closer examination, he also found iron and glass beads that had resulted from the intense heat unleashed by explosions in the air and sand.

“It is of course not surprising that shrapnel was added to the Omaha Beach sand at the time of the battle, but it is surprising that it survived 40-plus years …,” wrote McBride and [Dane] Picard, currently a professor emeritus at the University of Utah, in an article for Earth Magazine last year….

McBride reported that 4 percent of the sand is made up of these bits of shrapnel ranging in size from very fine to course (0.06 to 1 millimeter).

The figure is probably slightly lower today, as each year a bit more rusts away; still, that’s a remarkable figure—an unexpected legacy of brutal combat. The full report of their analysis appeared in the September issue of The Sedimentary Record, published by the Society for Sedimentary Geology.